Megafire study suggests today’s megafires, at least in the southwestern U.S., are atypical

From SMU (Southern Methodist University) comes this press release which really isn’t surprising. North America didn’t have a forest fire suppression program for the last 1400 years, so there wasn’t a fuel buildup issue like we have today, forest floors were cleansed naturally by non-catastrophic fires.

Unprecedented study relies on more than 1,500 years of tree-ring data and hundreds of years of fire-scar records gathered from Ponderosa Pine forests

Today’s mega forest fires of the southwestern U.S. are truly unusual and exceptional in the long-term record, suggests a new study that examined hundreds of years of ancient tree ring and fire data from two distinct climate periods.

Researchers constructed and analyzed a statistical model that encompassed 1,500 years of climate and fire patterns to test, in part, whether today’s dry, hot climate alone is causing the megafires that routinely destroy millions of acres of forest, according to study co-author and fire anthropologist Christopher I. Roos, Southern Methodist University, Dallas.

The researchers found that even when ancient climates varied from each other — one hotter and drier and the other cooler and wetter — the frequencies of year-to-year weather patterns that drive fire activity were similar.

The findings suggest that today’s megafires, at least in the southwestern U.S., are atypical, according to Roos and co-author Thomas W. Swetnam, the University of Arizona. Furthermore, the findings implicate as the cause not only modern climate change, but also human activity over the last century, the researchers said.

“The U.S. would not be experiencing massive large-canopy-killing crown fires today if human activities had not begun to suppress the low-severity surface fires that were so common more than a century ago,” said Roos, an assistant professor in the SMU Department of Anthropology.

Today’s extreme droughts caused by climate change probably would not cause megafires if not for a century of livestock grazing and firefighting, which have combined to create more dense forests with accumulated logs and other fuels that now make them more vulnerable than ever to extreme droughts. One answer to today’s megafires might be changes in fire management.

“If anything, what climate change reminds us is that it’s pretty urgent that we deal with the structural problems in the forests. The forests may be equipped to handle the climate change, but not in the condition that they’re currently in. They haven’t been in that condition before,” Roos said.

Study combines fire-scar records and tree-ring data of U.S. southwestThis new study is based on a first-of-its-kind analysis that combined fire-scar records and tree-ring data for Ponderosa Pine forests in the southwest United States.

Earlier research by other scientists has looked at forest fire records spanning the years from 1600 to the mid-1800s — a climate period known as the Little Ice Age — to understand current forest fire behavior. Those studies have found that fires during the Little Ice Age occurred frequently in the grasses and downed needles on the surface of the forest floor, but stayed on the floor and didn’t burn into the canopies.

Critics dispute the relevance of the Little Ice Age, however, saying the climate then was cooler and wetter than the climate now. They say a better comparison is A.D. 800 to 1300, known as the Medieval Warm Period, when the climate was hotter and drier, like today’s.

Scientists who favor that comparison hypothesize that forest fires during the Medieval Warm Period probably were similar to today’s megafires and probably more destructive than during the Little Ice Age.

Tree rings and fire scars provide the evidence for moisture, drought and burn activityScientists rely on tree rings not only to calculate a tree’s age, but also to determine wet and dry weather patterns of moisture and drought. Similarly, scientists’ best evidence for fire activity is the scarring on tree rings that dates the occurrence of fires. While tree-ring data for climate are available for long time periods, annual forest fire records don’t yet exist for the Medieval Warm Period.

In response to the need for data, Roos and Swetnam tested the Medieval Warm Period hypothesis by calibrating a statistical model that combined 200 years of Little Ice Age fire-scar data and nearly 1,500 years of climate data derived from existing tree rings. With that they were able to predict what the annual fire activity would have been almost 1,500 years ago.

They discovered that the Medieval Warm Period was no different from the Little Ice Age in terms of what drives frequent low-severity surface fires: year-to-year moisture patterns.

“It’s true that global warming is increasing the magnitude of the droughts we’re facing, but droughts were even more severe during the Medieval Warm Period,” Roos said. “It turns out that what’s driving the frequency of surface fires is having a couple wet years that allow grasses to grow continuously across the forest floor and then a dry year in which they can burn. We found a really strong statistical relationship between two or more wet years followed by a dry year, which produced lots of fires.”

“The best way to look at how fires may have varied — if climate were the only driver — is to do this type of modeling,” Roos said. “Our study is the first in the world to go this far back using this methodology. But this method can be used anyplace for which there is a fire-scar record.”

The study’s tree-ring-derived climate data are from the southern Colorado Plateau, a region that includes the world’s largest continuous stand of Ponderosa Pine stretching from Flagstaff, Ariz., into New Mexico. Large Ponderosa Pine forests have existed in the area for more than 10,000 years.

Fire-scar data for the region go back as far as the 1500s, but are most prevalent during the Little Ice Age period. Fire scientists have analyzed fire-scars from hundreds of trees from more than 100 locations across the Southwest. All fire-scar data are publically available through the International Multiproxy Paleofire Database, maintained by the federal National Oceanic and Atmospheric Administration’s paleoclimatology program.

Ancient fires were frequent, but didn’t burn the forest canopyFire scientists know that in ancient forests, frequent fires swept the forest floor, often sparked by lightning. Many of the fires were small, less than a few dozen acres. Other fires may have been quite large, covering tens of thousands of acres before being extinguished naturally. Fuel for the fires included grass, small trees, brush, bark, pine needles and fallen limbs on the ground.

“The fires cleaned up the understory, kept it very open, and made it resilient to climate changes because even if there was a really severe drought, there weren’t the big explosive fires that burn through the canopy because there were no fuels to take it up there,” Roos said. “The trees had adapted to frequent surface fires, and adult trees didn’t die from massive fire events because the fires burned on the surface and not in the canopy.”

Today’s huge canopy fires are the cumulative result of human activityThe ancient pattern of generally small, frequent fires changed by the late 1800s. The transcontinental railroad had pushed West, bringing farmers, ranchers, cattle and sheep. Those animals grazed the forest floor, consuming the grasses that fueled small fires but leaving small saplings and brush, which then grew up into dense, mature bushes and trees. In addition, the U.S. began to restrict the traditional land use of the region’s Native American communities, including confining them to reservations. This removed another source for frequent surface fires in the forests — burning by Native Americans for horticulture and hunting.

By the early 20th century, the U.S. Forest Service had been established, and fighting fires was a key part of the agency’s mission. Without continuous fuel, fires on the forest floor ceased.

“Many of our modern forests in central Arizona and New Mexico haven’t had a fire of any kind on them in 130 or 140 years,” Roos said. “That’s very different from the records of the ancient forests. The longest they would have gone without fires was 40 or 50 years, and even that length of time would have been exceptional.”

The research reported in The Holocene is the basis for a new four-year, $1.5 million grant from the National Science Foundation in which Roos and Swetnam are co-principal investigators. That project will examine how human activities have changed forests and forest fires over the past 1,000 years of Native American occupation, as well as the influence of droughts during the Medieval Warm Period and Little Ice Age in New Mexico’s Jemez Mountains. — Margaret Allen

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see http://www.smuresearch.com.

73 thoughts on “Megafire study suggests today’s megafires, at least in the southwestern U.S., are atypical”

Of course studies like this were tailor-made for a blind, bumbling media that will generate headlines that fires are growing worse due to human activity and the takeaway will be that someone has to do something about AGW. The humanity.

I write about forest fires in DSYC:

Fire is another expression of the ever-changing distribution of water. A wet, cool forest will seldom burn, but not a single forest stays wet and cool forever. What is required to generate a large forest fire is a period of relatively abundant precipitation followed by a period of relatively limited precipitation. Or, in other words, normal meteorological variability.

Fire photographs so well that commentators feel especially free to associate it with global warming. In the Californian west, where I am from, there are wet and rainy seasons. This has been true throughout the Holocene climate epoch. Yet, it is a safe bet that TV screens will light up in July, August, and September with this year’s crop of Western fires, and somebody somewhere, watching and listening, will conclude that the brilliant orange and reds were caused by too much carbon dioxide in the atmosphere and the warming that it produced. But have any of the television correspondents studied American fire history or world fire history?

In the 1920s, according to the U.S. Forest Service, fires burned an average of 26 million acres a year. During the 1930s, they burned an average of 39 million acres a year. During the 1940s, the total was 22 million acres a year. During the 1950s, 10 million acres a year. During the 1960s, the total burned was 5 million acres a year. During the 1970s, 4 million acres a year. During the 1980s and ’90s, fires again burned an average of 5 million acres a year. The record for the 2000s shows an annual average of 7 million acres a year. Thus, the overall trend for the past century is overwhelmingly in decline. If the number of acres burned increased next year to the levels of the 1920s and ’30s, what do you suppose the newspaper headlines would read?

This is really interesting, but unsurprising. The same pattern can be seen in Australia.

After the dreadful wildfires of 3 years ago in Victoria I have been aghast to see the huge amount of understorey growth, following all the rain they’ve had. It’s all ready to burn again with the next long, hot summer. The most horrifying thing is that there is, once again, a lot of young growth along the roadsides, all ready to allow fire into the tree canopies. These are roads needed for escape. Frightening.

Interesting, but the theory that today’s fires can be more severe because forest (mis)management practices lead to higher fuel density have been around for quite some time. Nice to hear “Little Ice Age” and “Medieval Warm Period” in a discussion of potential affects of climate change.

if you think the SW US has a megafire problem, try Australia with its flora dominated by species who actually require fire to reproduce and assist the process by manufacturing flammable oils in their leaves. The removal of the Aboriginal population from the landscape with their management by fire for tens of thousands of years coupled with ecozealots who treat our native landscapes as somthing fixed and attack any attempt to introduce alternative management methods similarly results in wildfires that kill hundreds of people at a time. The death rates are far worse than 100 or 150 years ago despite all the available technology and means of escape.

Luckily that article only used the word “model” or “Modelling” 5 times. I’ve developed a model that clearly shows the value of an article scales with the inverse of the sum of “model” terms used. It’s the bogosity forcing term.

Let me put in a plug for a book I just read by America’s greatest living historian of fire, Stephen Pyne.

The book is _Year of the Fires: The Story of the Great Fires of 1910_. Pyne’s book doesn’t just provide great narrative, it shows how progressive leaders like Gifford Pinchot used the disasters of 1910 to solidify into policy their ideological aversion to natural fires and their radical commitment to a “zero tolerance” policy for both natural burning and controlled burning. That approach, which contradicted the advice of an older generation of naturalists such as John Wesley Powell, remained the established conventional wisdom until it started to break down three generations later, during the late 1980s and is now in tatters.

I find some rough parallels between the current man-made-dangerous climate change orthodoxy and the 20th century progressive orthodoxy about the role of fire in nature (which Pyne himself mentions once or twice in passing). Both place a heavy emphasis on technocratic control, and the empowerment of an elite expert class whose views are not to be questioned. Doubtless there are big contrasts between the old Pinchotian progressives and the current crop of Malthusian ecologists (the former were not ideologically opposed to resource extraction), for example. But the manipulation of scientific data to support a predetermined view is abundant in both cases.

Thinking about Pyne’s book and the long time period it took before the anti-fire ideology began to be questioned, I have to wonder how long the current anti-CO2 ideology will hang on. Unfortunately I’m somewhat pessimistic about this. As Thomas Kuhn said about scientific paradigms, they normally change via death more than by argument.

Smokey Bear, call your office. You’ve got some ‘splainin’ to do! Seriously, fire suppression was a consensus opinion and is equivalent to geo-engineering schemes. It should be taken as a recent object lesson about the unintended consequences that arise when actions are applied to half-understood “problems.”

So 4 or 5 non-GW related reasons for the fires yet somehow still linked to GW? Jeez. There are definately human reasons for these fires: different management styles from the native americans, houses in areas where no one lived 50 years ago (hence didn’t care about the fires), campers, vandals, the previous management style of extinguishing every fire regardless of how remote. Remember fire jumpers? Talk about a crazy as* job.

The SW is naturally dry, that has nothing to do with GW. There are practically zero forest fires in the NE and we have more trees than we had 200 years ago.

The “unprecedented” phrase applies to Swetnam & Roos using fire signatures
in Ponderosa Pines … not necessarily the overall data trends as they reflect
temperature or moisture over the 1,416 year period.

This earlier study is well worth reading, especially their data , graphs and
interpretations of what went on and what it meant in terms or fire signatures
in these huge trees in the American west during the LIA and the MWP.

Their data maps these periods , and similar climate fluctuations in the
American Southwest in a very clear manner.

However, just because the LIA and MWP and other warm/cold periods
seem to show up in tree rings in our Southwest doesn’t these climate phases
happened anywhere else in the world around the same times.

IIRC, the extensive Longleaf pine forests of the Gulf coastal plains typically had surface burns every couple yrs — mostly lightning-caused. Understory fuel never had a chance to build up. This was once one of the richest ecosystems in the world, rivaling tropical rain forests in species diversity.

We know what happens in warm temperate zone forests of similar size to California, without people, because we have one here in Western Australia called the Great Southern Woodland (about 1/2 the size of California. Although if you include the scrub forest to the north, comparable in size to California).

Forest fires burn unchecked throughout most summers. Some years fires burn throughout the winter.

In the 1970s one fire burned for 2 years across 30 million acres. About a third of the size of California.

BTW, the fires start from lightning strikes and we can assume they have occurred for a very long time.

I have served in the nsw rual fire brigade for 50 years in the old days we did not have any problem with burning off but in the 80s the greens come and soon stopped all the burns. from that time we have had major fires that took lives and property right across australia and the greens still say they are saving the trees they are wrong a very hot fire kills the trees .you cannot change somebody who has only half a brain . PLEASE you will make a million if you can get a greeny to use at least some of his left side brain or right side it is up to you. God bless Australia because we need all the help we can get

Today’s mega forest fires of the southwestern U.S. are truly unusual and exceptional in the long-term record, suggests a new study that examined hundreds of years of ancient tree ring and fire data from two distinct climate periods.

Conduct a study rather than ask anyone involved in fighting forest fires in the past sixty years.

Some species of pines *require* periodic fires through the area — their cones won’t open to expel the seeds unless they’re scorched.

“If anything, what climate change reminds us is that it’s pretty urgent that we deal with the structural problems in the forests”
==============
If anything, what climate change reminds us is that it’s pretty urgent to convince the government that we can manage everything…..there’s good government money in it…………

Various California plants with different fire mediated germination strategies. Some depend on heat and scorching, others use smoke…

It is an ecosystem that has evolved to depend on forest fire….

I agree with the folks pointing out the “no burn” for way too long followed by the “no putting out”. Just brain dead. Darned near destroyed Yosemite a few years back. Eventually the public outcry had them control it.

To fix the national forests (i.e. get back to normal) will take a lifetime of controlling modest to small size burns. Nature had a patchwork of different ages so it didn’t all burn at once.

“It’s true that global warming is increasing the magnitude of the droughts we’re facing, but droughts were even more severe during the Medieval Warm Period,” Roos said.

While it is nice that the MWP is acknowledged in their narrative, I know of no real evidence that global warming is increasing the magnitude or frequency of droughts. How can it? Any warming is accompanied by increased evaporation and subsequent precipitation overall. Some of that moisture must find it’s way to drought areas making drought less severe as demonstrated in the Sahara regions. Yet this claim is repeated numerously through-out the article.

When are these researchers going to give proper examination and testing to their initial assumptions, so that some credibility remains for their study results? Making unsubstantiated assumptions seems to be a requirement for consensus science. GK

Since the late 1800’s native grasslands in the SW have been invaded by cheatgrass (BRTE). Originally a Southern European species, it’s hardier, dries more quickly and burns hotter than native species. It’s the major contributor to the change in fire frequency and intensity over the last few hundred years.

How many of today’s fires are started by the carelessness of people or even intentional started by people. I would imagine most ancient fires were started by lightning and not a gallon of gasoline and a Bic lighter. Also, once these ‘wild’ fires get started often it will encounter a house or a barn, etc. which seem to burn a lot hotter than the natural landscape. It is amazing when these are reported in the news how many are actually caused by humans, yet they are still referred to as ‘wild fires’.

In response to the need for data, Roos and Swetnam tested the Medieval Warm Period hypothesis by calibrating a statistical model that combined 200 years of Little Ice Age fire-scar data and nearly 1,500 years of climate data derived from existing tree rings. With that they were able to predict what the annual fire activity would have been almost 1,500 years ago.

After living in Colorado for 40+ years, and hiked the mountains, forests and plains. Even during the “wet” years, there is virtually no precipitation from the end of May until the beginning of August, The live ponderosa pines drop moisture content to 10-15%, like dried wood. There is nothing to keep the ‘canopy’ from burning. Does a forest of 15-20′ trees even have a canopy? Looking out my window at the forest across my road, there is nothing that could be construed as a canopy.

The focus on forest fires is another example of a limited study. It’s true there wasn’t a fire suppression process in place in recent decades, but there was an extensive use of fire for hunting and defense by humans since they arrived in North America prior to arrival of Europeans.

A very good overview of these fires and the role of humans in causing them is provided in the Summer issue (Volume 60. No.3. 2000) of Fire Management. There is a very interesting graph showing offshore sediments and the occurrence of charcoal related to land based fires.

Limiting the study to forest fires is another problem with the study.

I recall an entry in the Hudson’s Bay Company journals for the 1790s that says the Indian’s report the whole of the Prairies are on fire. Grass fires were a major factor in the ecology of North America and undoubtedly spread into neighbouring forest regions. There is a famous painting by Paul Kane of a praise grass fire. The southern edge of the boreal forest is extending south partly because these fires are now suppressed. Communities like Carberry Manitoba installed municipal water supply primarily to fight grass fires that threatened their homes on a regular basis.

None of this is surprising because grasslands, variously called savanna, pampas, steppes, tundra, Prairies, and Great plains, cover a reported 13.8 percent of the land mass and are overlooked in recent climate studies.

Koppen recognized them in his climate classification system but that was because he featured the role of precipitation in his B classification. Since then, with the IPCC focus on temperature, they have dropped out of the picture. I am not aware of any estimates of the input and output of CO2 from this significant source and sink, but then we didn’t start measuring them for the vast boreal forest until relatively recently and then in limited studies.

Wow – this is becoming a bit surreal. The link between fire severity and AFS (anthropogenic fire suppression) is VERY well known and has been for quite some time.

I wonder, exactly how much does a study like this receive in grant $? It seems anything can get funded based on tie-in to CAGW, but exactly how much $ are we talking about? If the money is available their will always be takers. A good feedback mechanism would be to require publicly funded grant recipients to publish the amount of the grant alongside the work. That will help the public decide if they are truly getting value for their tax dollars.

The percentage of wildland/forest fires started by human activity is stunning.
As just one example, a building contractor using a power tool on a jobsite started a 17,000 acre forest fire about 3 miles from my house. Power lines sparked a fire that ripped through a neighborhood not far from there and destroyed homes. A poor old guy put fireplace ashes out and started a huge wildland fire that destroyed homes. Huge fires, all human caused. Natural fires have been few and far between.

From a standpoint of here in AZ, a very small portion of the fires are from human sources. However, the ones that you hear about and caused the most damage over the last few years are the result of carelessness and pyromaniacs. However, during a normal monsoon season, a multitude of fires are started from lightning strikes and are usually put out very quickly by the forest service. I have to disagree with your “a building burns hotter” statement since many fires in AZ do not even come close to structures, it is the excessive buildup of undergrowth that causes the fires to burn too hot allowing the flames to travel to the crown of the trees. Several individuals have already mentioned why we have more severe fires now than in the past and that has to do with the progressive/green mindset of forest maintenance which many for the forestry departments, particularly NAU, in AZ are fighting to reverse.

The Eastern US forests were different back then. Most of the trees in Appalachia, for example, were American chestnut; the “Redwood of the East”. These trees were absolutely huge and grew much taller than the trees that populate that area today. These trees grew rapidly and would reach an excess of 100 feet tall and commonly being over 8 feet in diameter were pretty hard to burn from a fast moving fire.

I can’t help but wonder how much different it makes that the species inhabiting that particular area have changed since the LIA and MWP.

One reason for fire suppression has been to protect logging interests. Someone with a reasonably valuable stand of timber probably gets a bit upset when it burns. This might be particularly true in cases where the local population depended on those trees for their livelihood.

From the article: “Today’s extreme droughts caused by climate change probably would not cause megafires if not for a century of livestock grazing and firefighting, which have combined to create more dense forests with accumulated logs and other fuels that now make them more vulnerable than ever to extreme droughts. One answer to today’s megafires might be changes in fire management.”

I’m having trouble getting a handle on this. It poses more questions than it answers. Extreme droughts are common throughout history. I believe they are saying that grazing and fire suppression techniques are causing the megafires, but are extreme droughts really a product of climate change or are they merely due to natural climate variability? In fact, is climate change a result of natural climate variability or largely or partially human-induced? This last, of course, is the great question in the great debate of our time.

The other question I have is this: do megafires have adverse effects beyond those of the historic limited types of fires? I’ve seen the consequence of a mega fire in the Oakland Hills in 1991 and I also saw the area, which had a lot of steep terrain, regenerate rather quickly in the decade after. That was actually a wildland fire within the city limits that destroyed three thousand houses, so it might not be relevant here.

However, I own a parcel here in north San Diego County that burned shortly after I bought it in 2000. It (the chaparral) is almost entirely regenerated now, and I am making sure that in the event of another fire, my house will not burn. The lot had not burned in 60 years, which I was told was an unnaturally long time. And yet, everything seems to be coming back fine, although with an increase in construction in the area and the seeding that the state did afterward, there are a lot of invasive and/or non-native species of plants now thriving.

Here is the final paragraph of that letter:
“Do people cause fires? Absolutely. Will bad fires happen again? They always have and always will. Let’s not use climate change as the easy way out or use it for sensational journalism when it is a very small part of the equation.”

“The U.S. would not be experiencing massive large-canopy-killing crown fires today if human activities had not begun to suppress the low-severity surface fires that were so common more than a century ago,” said Roos, an assistant professor in the SMU Department of Anthropology.”

More than a century ago? Even 50 years ago agricultural fire suppression was blankets and urine, if you had any of either, so until recently it is doubtfull that fire suppression had much effect on anything.

“Today’s extreme droughts caused by climate change probably would not cause megafires if not for a century of livestock grazing and firefighting, which have combined to create more dense forests with accumulated logs and other fuels that now make them more vulnerable than ever to extreme droughts. One answer to today’s megafires might be changes in fire management.”

Well this is something I have had personal experience in. I was a Co-pilot on DC-6/7 airtiankers from 1988-to 1997 .One of my pet peeves was the lack of a coherent policy on conducting fire
suppression and control. More than once we set out to fight a fire that was a result of a controlled burn going over the hill in conditions that were forecast to be not good.This still happens regularly.
The ignoring of Urban/wild land interface and the restrictions on your right to keep fire from your
home.Or, in some cases the ignoring the fact that you live an area that can burn.and you do not take precautions that can enhance a fire it;s path. The waste of resources and people to fight
a fire that is not going to do anything but burn scrub, trees and/or sagebrush. Time and again we
would be dispatched to a fire literally in the middle of nowhere, like say in the middle of northern Nevada, and be the only airtanker on a 15 mile flame front.Now what? Or better yet, a two hour flight from Fairbanks north to a tundra fire with no even an Inuit village threatened.
Now the pendulum has swung the other way. Fewer crews, equipment, and roads.The forests
are clogged with brush and debris. (No I am not a believer in putting all fires out all the time,
policy that got us into trouble,) We now are setting ourselves up for another “Big Burn of 1910″
and it will be blamed on “Climate Change.” instead of stupidity..
BTW there are, approx. 17 airtankers nationwide. down from 35 a few years ago.Helicopters,
and smokejumpers are also in decline. Now What?

Dr. Bill Wattenburg has been talking about this buildup of underbrush problem on his radio program for at least 10 years so it can’t be unknown to scientists in the field. Apparently latest fires burn so hot that they practically sterilize the soil and even the seeds + pinecones that need fire to begin the germination process are being damaged instead.

Texas is attempting to deal with the convulsive megafires by allowing and promoting controlled burns. A lot of ranchers are doing it. It will also help the groundwater by controlling mesquite and juniper. We have a long way to go. SMU is just echoing the conclusions already reached by most of the state, local, and college people who are looking at this. I expect that long term, Texas will come to mandate the use of controlled burns or offer landowners incentives to manage properly with the money coming from the municipal water districts, whose customers will have a more resilient watershed as a result.

Does anyone know how Roos and Swetnam avoided the survivor sampling bias pitfall? It might be possible to look at fire scars on 500 year old tree-ring sets, but you can do that only on trees that survived long enough to be sampled. A major crown-type fire 300 years ago would have removed those trees from the sampled population.

This article reminds me of a story about the Blackett Operations Research Group in WWII England. I wrote it up at ClimateEtc March 7, 2012 with links.

My OR Professor, Gene Woolsey, told a story at the end of the first day of class. A WWII pilot noticed that some RAF officer with a clipboard was going out to the flightline after they landed from every mission. The pilot one day ask what he was doing. The RAF officer explained that he was “studying bullet holes on the bombers and fighters to learn attack pattern and where armor might be most effective.” The pilot having just returned after a hard mission asked incredulously, “Did it ever occur to you that you only see the planes that COME BACK!?!?” My professor closed with, “Don’t let this happen to you.”

While researching this story I found a 2007 report by Jaap de Rue, that reports the story slightly differently. Patrick Maynard Stuart Blackett lead that OR group and in their report to the RAF recommended armoring the least damaged areas since only planes that came back from Germany were included in the survey, his team reasoned that the untouched areas were apparently the most vital areas.

How true is the story? There is no doubt in my mind that the OR Group did go out and study battle damage with recommendations for changes to armor. And no doubt some people initially thought the returning planes were a reliable sample of damage from attack. But I have no doubt that the leaders quickly realized that the “planes that come back” were NOT a random sample of battle inflicted, but a highly biased one. This is the whole moral of the tale.

It is not possible to inspect the planes shot down. All you have are the planes that come back. You have to work with biased data. Understand the bias. Be aware of it, not blind to it. Make your recommendations accordingly.

Just so, it is not possible to obtain the tree ring sets of 500 year old trees when they were killed by a crown-fire 200 years ago. How did the authors avoid and account for that survivor sampling bias?

I was taught about fire-suppression leading to accumulating undergrowth and more damaging fires while at summer camp in the early 1970s

I remember taking a cross-country trip with my parents in the mid-70s and hearing that from every park ranger in every park from Colorado to California and back.
Once hiking and camping in Maine we came across the most amazing clearing. Stepping out of the forest into an area free of trees about 200-300 meters across but as far as the eye could see from left to right. The space was filled with 2m tall blackberry bushes groaning under the weight of all the huge, juicy blackberries. The place of was lousy with bears, but they didn’t have time to pay any attention to some scouts. They were too busy eating.
Our guide explained that the state sold logging tracts that were very narrow, but miles long, so the logging would create fire breaks.

Ferd says:
May 18, 2012 at 7:20 am

It is amazing that it takes “scholars” with big degrees and tree ring studies to figure out what previous generations knew by intuition.

Reminds me of the scene from “The Gods Must Be Crazy II” when fleeing from a grass fire, the Kalahari tribesman lights a fire. He lets it burn, then they all step into the area cleared by his burn. The pursuing flames go around them because the fuel has already been consumed. Literally fighting fire with fire.

Harold Ambler says (May 18, 2012 at 4:26 am): “I was taught about fire-suppression leading to accumulating undergrowth and more damaging fires while at summer camp in the early 1970s in the Santa Cruz Mountains.”

I remember reading the same thing in the literature while a grad student in the early 70s. In the 80s, while we were visiting Yosemite, a guide told us about the controlled burns they were using to manage the park, and pointed out a small redwood that had sprouted after a burn some 12 years before. In fact a controlled burn was in progress at the time.

…..One reason for fire suppression has been to protect logging interests. Someone with a reasonably valuable stand of timber probably gets a bit upset when it burns. This might be particularly true in cases where the local population depended on those trees for their livelihood.
___________________
Sorry Crosspatch, logging interest are not that stupid. A controlled burn is used to clean up the under-story, return nutrients to the ground and to prevent the build up of material that can cause really destructive fires. I can drive along the highway near my place and point out all the controlled burn sites here in North Carolina.

It is the econuts who get laws passed to prevent controlled burning and to prevent the clearing of brush who are directly responsible. As far as I am concerned this is a Cover Your Butt study so they do not find themselves in court where the belong.

Ever since the insurance and real estate industries matured at the end of the 19th century there has been an unusual (unPREcedented, even!) amount of surpression going on. Guess what, no small burns? BIIIIIIIIG burn!

I’m having trouble getting a handle on this. It poses more questions than it answers. Extreme droughts are common throughout history. I believe they are saying that grazing and fire suppression techniques are causing the megafires, but are extreme droughts really a product of climate change or are they merely due to natural climate variability? …

You’re apparently assuming that fires happened after extreme droughts. Many places used to be burned several times a decade, drought or not. Because during a dry spell, the grass or underbrush was likely to be set on fire on purpose. Often this was not done during the driest part of the year, because a slowly crawling fire was desired, to clear the underbrush or keep trails open. So there was not a twenty or fifty year accumulation of stuff to burn.

Does anyone know how Roos and Swetnam avoided the survivor sampling bias pitfall? It might be possible to look at fire scars on 500 year old tree-ring sets, but you can do that only on trees that survived long enough to be sampled. A major crown-type fire 300 years ago would have removed those trees from the sampled population.
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Exactly.

We have massive and very destructive forest fires regularly in Australia. It is one of the reasons for the dominance of eucalypts in our landscape – they regenerate very quickly even after fires which leave not so much as a twig for hundreds of square miles. Forest fires happen every year, and are usually started by lightning strikes.

While it is true that low intensity burns can reduce the impact of fire, the reality is that when a forest fire and hot, dry winds get together there is no way of slowing or stopping it using human resources. You just have to wait for a wind shift, heavy rain or the fire moving into less densely forested areas where the intensity is reduced and the fire can be fought.

As in the US, the native inhabitants used fire to clear portions of the landscape before European settlement. But, the country is so large and the inhabitants were so few that massive areas were never burned off through human intervention. Just like today, every summer there were naturally caused, high intensity forest fires which destroyed everything in their path and eventually went out again for natural reasons.

The native Americans regularly burned the forests. This is why long leaf pine was the primary wood of east Texas; it was highly resistant to forest fire. It was the more recent immigrants who stopped the annual or biannual fires. The result is that a lot of burnables end up building up. Furthermore, it’s become more and more difficult to give your forest a light burn due to EPA considerations.

This was done throughout the US. The intention was to make the land better for hunting deer and growing corn. Nowadays we could probably do something similar with diesel powered hydraulic equipment but at the time, burning was very effective.

When Lewis and Clark crossed the country, the forests in the Pacific NW were park like due to the regular burns. If you try this now you end up having to hack through incredible berry tangles.

Gail Combs says:
May 18, 2012 at 11:38 am
“Sorry Crosspatch, logging interest are not that stupid. A controlled burn is used to clean up the under-story, return nutrients to the ground and to prevent the build up of material that can cause really destructive fires. I can drive along the highway near my place and point out all the controlled burn sites here in North Carolina.”

Unfortunately I have seen cases here in WY where in the national forest, loggers have NOT cleaned up toppings and debris after logging on public lands whether due to negligence on their part, since it is not their land/trees, negligence on the part of the Forest Service in rules or enforcement of rules, I do not know. However, it would seem that all the good done relative to fire prevention from thinning out the trees is negated by leaving the trimmings behind on the forest floor.

…..Unfortunately I have seen cases here in WY where in the national forest, loggers have NOT cleaned up toppings and debris after logging on public lands whether due to negligence on their part, since it is not their land/trees, negligence on the part of the Forest Service in rules or enforcement of rules, I do not know. However, it would seem that all the good done relative to fire prevention from thinning out the trees is negated by leaving the trimmings behind on the forest floor.
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It depends on the state and it depends on the contract with the land owner. In New Hampshire they have to clean up their messes. In NC it is up to what is in the contract. However with a coal plant that also burns wood not far away it pays to chip the trash and haul it to the coal plant to be bought as “bio-fuel”

Around here it is the individual land owners who thin and burn to get the best “crop” of pine.

North America didn’t have a forest fire suppression program for the last 1400 years, so there wasn’t a fuel buildup issue like we have today, forest floors were cleansed naturally by non-catastrophic fires.

You are dead wrong about that, Anthony. In fact, it was anthropogenic (human-set) fires that prevented megafires, and not just for 1400 years but for ten times that long.

Large Ponderosa Pine forests have existed in the area for more than 10,000 years.

Human beings have existed in the area for at least 13,500 years and probably 15,500 years. That means humans predated the pine trees by many millenia. Look it up.

When human beings arrived on this continent, they brought with them ~1.8 million years of burning experience. Practice makes perfect.

The Precontact (before Euro-American) forest development pathways were mediated by frequent, purposeful, anthropogenic fires deliberately set by skilled practitioners, informed by long cultural experience and traditional ecological knowledge in order to achieve specific land management objectives. At a landscape scale the result was maintenance of an (ancient) anthropogenic mosaic of agro-ecological patches. In the absence, over the last 200 years, of purposeful anthropogenic fires, the anthropogenic mosaic has been invaded and obscured by thickets.

The open, park-like pinenut orchard/forest that existed in Precontact times in the Southwest was constructed by people. Proof is that nowhere are such forest structures arising “naturally” today.

Megafires are caused by quantity and continuity of fuels. Lightning fires are entirely inadequate at reducing biomass or breaking up fuel continuity.

The First Residents were not so stupid as to allow catastrophic fires to destroy their means of survival. They took precautions by burning in cool seasons. That fact has been well established.

When “scientists” deny historical human influences on the environment, they display extreme cultural bigotry tantamount to racism. It is Victorian junk science, something we supposedly advanced beyond 160 years ago, but it hangs on like boil on the neck of science.

Please try to acknowledge history. Try not to think that you, today, are the first human being ever to walk the earth. Don’t be a cultural bigot. The truth will set you free.

And by the way, to those of you who think fire suppression is a bad thing, please underestand that without it the entire Western US would be uninhabitable. Chico, for instance, would be scorched earth wasteland without a living soul in it.

The Australian eucalypt forests were managed by the aboriginals for 40k years prior to European settlement. Their management tool, fire, was administered with the experience gained in countless generations of “fire stick farming”. This practice not only made the bush more open and easier for hunting, but promoted the growth of “green pick”, new grass attractive to kangaroos and other target species.
The progressive closure of public forest land in poorly managed National Parks, with the unnatural exclusion of fire, led to intense wild fires. These fires culminated in the Victorian “Black Saturday Fires” of February 2009, which cost 173 lives. Thankfully there now seems to be an increased awareness that regular fuel reduction burning is essential for public safety.

Bob in Castlemaine, some parts of the country were burned by Aboriginal people pre-European settlement – but most were not. There simply weren’t that many people living on this vast continent, and burning was small scale and localised. The vast forests of the Great Dividing Range, for example, were not routinely burned, because (a) very few people lived there; and (b) just like today, it is extremely difficult to control a fire in that rugged terrain once it gets started.

There is a lot of ‘noble savage’ mythology around about Aboriginal burning, which undoubtedly occurred, but was dwarfed by the massive wildfires which started and finished naturally every summer, just as they do today, despite a much larger population and the availability of firefighting resources.

Mark Twain describes accidentally starting a wild fire (somewhere out west) in “Roughing It.” It started from their cooking fire, as they walked down to a lake to get water. After a brief time spent attempting to halt the spread, he and his pal had to flee out onto a lake. As night came on they could see the fire had gone over the nearby hills and was spreading up the more distant ranges. Having blackened all the nearby landscape, the next day they decided to quit camping and try something else.

I now want to go back and reread that brief description. It was only a few pages. As I recall, he didn’t feel all that guilty, and didn’t flee to escape the wrath of Smokey the Bear. I would guess it occurred 1870-1880.

What does this prove? Nothing much, unless it is that fire spreads very swiftly out west. Also that it can be dangerous to associate with writers.

Johanna refers to “‘noble savage’ mythology around about Aboriginal burning”.

It is true that there was little burning in the alpine country, but that was more because access was seasonal and the open nature of alpine vegetation meant there was little point in doing so. But there is evidence in the numerous eyewitness accounts of famous early explorers and settlers to substantiate that aboriginal burning was wide spread elsewhere throughout the forests and woodland of Australia. This reference identifies just a few of the more distinguished amongst the many people of the time who documented what they saw; they include Captain James Cook, Sir Joseph Banks, Matthew Flinders, Governor Arthur Phillip, Gregory Blaxland, Allan Cunningham, Captain Charles Sturt and Major Thomas Mitchell (see pages 2 to 5).

Even today aboriginal burning is still practiced in parts of northern Australia. The assertion that aboriginal burning did not occur is nothing more than a myth created by the environmental lobby to justify the prevention of rational fire management regimes. Like so much in contemporary post normal science, it not based on evidence but is justified almost solely on the basis of the so-called “precautionary principle”.

Bob in Castlemaine is absolutely correct when he says, The assertion that aboriginal burning did not occur is nothing more than a myth created by the environmental lobby…

It is racist myth used to bolster their false assertion that human beings are toxic to the environment.

The facts are clearly that technological man and nature have co-existed since the evolutionary appearance of Homo erectus 1.8 million years ago. We are and always have been the caretakers of nature.

But a certain virulent philosophy seeks to tear down man, to paint man as a toxic disease on the Planet. They assert that man is evil, that the human population must be heavily culled, and that the survivors must be herded into concentration camps by “wise” eco-masters.

It’s just the same old ugly fascist-communism under a green hat.

Despite the horrors wrought by that philosophy in the 20th Century, it has not gone away.

That’s why it is essential to point it out and deconstruct that philosophy when it rears its ugly head, whether it takes form as bogus notions of human-caused climate change or deliberate erasure of human history.

PS to Gail: how did common knowledge 40 years ago (indeed for all of human history) become lost? Don’t tell me people just forgot. No, there has been an insidious campaign, to destroy knowledge for despicable anti-human purposes, that has been waged on society.

“There was way more carbon soot in the air and on the ground in forests and grasslands prior to industrialization. Because of human impacts, there now is way less.”

I ask you this question: Since 1900, where have the many billions (and billions and billions!) of pounds of fine particles of rubber and asphalt gone? The short simple answer is anywhere and everywhere.

I passenger care tire with an A treadwire rating will shed about a pound of rubber over its lifetime. Bulk rubber and asphalt do not easily catch fire. Very fine particles of rubber (known as rubber dust) are a fire hazard in industrial operations, and methods are undertaken to control and prevent accummlation of it in plants especially near electrical motors or equipment were a spark can occur.

Fine particles of rubber and asphalt could act as acelerants and might contribute to ferocity of wild fires in Southern Cailfronia. Home owners should wash any these particles off the roof of their house before the start fire season.

Modern synthetic rubbers are not degraded upon exposure to air and sunlight and to microbes due to addtion of UV protectents, anti-oxidants and anti-microbial agents.

To check for road dust in urban area or near alarge roadway, which is comprised of particles of soil, rubber, asphalt, sand from concrete,etc, dab a Post-It on any horizontal surface (e.g., the top of a car) after few days of no rain. Examine the blakened sticky under modest magnification (ca. 30-50x). The black flat flecks are rubber, the amorous paricles are from asphalt. The highly-refractory opaque spheres are sand from concrete. The flat, highly reflective small flecks re mica.

These are the particles you can see. There is class of particles (i.e., PM 2.5) you can not see unless you have compound microsope. I read that children that live major highways and commuter routes have higher rate of asthma than children who that do not live near these.

Johanna refers to “‘noble savage’ mythology around about Aboriginal burning”.

It is true that there was little burning in the alpine country, but that was more because access was seasonal and the open nature of alpine vegetation meant there was little point in doing so. But there is evidence in the numerous eyewitness accounts of famous early explorers and settlers to substantiate that aboriginal burning was wide spread elsewhere throughout the forests and woodland of Australia. This reference identifies just a few of the more distinguished amongst the many people of the time who documented what they saw; they include Captain James Cook, Sir Joseph Banks, Matthew Flinders, Governor Arthur Phillip, Gregory Blaxland, Allan Cunningham, Captain Charles Sturt and Major Thomas Mitchell (see pages 2 to 5).

Even today aboriginal burning is still practiced in parts of northern Australia. The assertion that aboriginal burning did not occur is nothing more than a myth created by the environmental lobby to justify the prevention of rational fire management regimes. Like so much in contemporary post normal science, it not based on evidence but is justified almost solely on the basis of the so-called “precautionary principle”.
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Bob, if you have ever flown up or down the Great Dividing Range, which extends for thousands of miles just inside the east coast of Australia, you will know that it is hardly an open alpine environment for the most. It is mainly incalculable billions of eucalypts which form an impenetrable barrier from the air. A few thousand Aborigines, dotted here and there, could not possibly have impacted that environment through burning without self immolating, and it just never happened.

I have never disputed that burning occurred, but I strongly dispute that the reason for huge bushfires which leave nothing but a pile of ash is the cessation of Aboriginal burning. The lightning strikes which caused the Canberra bushfires of 2003 (which I experienced) occurred in rugged and heavily forested country in the mountains. No-one could seriously suggest that lightning strikes and fires like that never occurred pre-European settlement. The reason this is now a political issue is that people live near the forest boundaries these days, and their property (and sometimes lives, sadly) are destroyed.

I absolutely agree that if people want to live in these places, they need to keep the land around their home cleared and so on. But anyone who has ever seen a 30 metre high wall of fire driven by hot westerlies (as I have) might share my view that living in these locations carries a small, but uncontrollable, risk of losing everything and/or being burned to a crisp, no matter what human interventions there are.

clipe says on May 19, 2012 at 4:58 pm:
Harold Pierce Jr says:
May 19, 2012 at 4:18 pm
I read that children that live major highways and commuter routes have higher rate of asthma than children who that do not live near these.

Where did you read that? A sister of mine was born in bucolic Clackmannanshire, Scotland with asthma circa 1958

I remember reading some time ago an article in the Vancouver Sun that investigators have found that asthma were more prevalent in young children living in dense cities near high traffic areas than those who living suburban or rural areas

And of course one only has to see how many types of tree and shrub, particularly in Australia, (I don’t know about the US flora), actually REQUIRE a good dose of heat for seed germination.
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Not only that, Andy, as I said above – catastrophic bushfires are probably the main reason for the dominance of Eucalypts in Australia. They regenerate quickly after fire and then poison the soil around them with eucalyptus oil and other toxins to kill off the opposition.

I can’t speak for US forests, but the notion that devastating fires are a new thing is utter nonsense in Australia.

USDA forest service published Fire Management Today in 2000 (#3) on the frequent use of low-level fires by native americans prior to 1900. http://www.fs.fed.us/fire/fmt/fmt_pdfs/fmn60-3.pdf
“Indian fire use, mostly for peaceful purposes, was so extensive that it shaped ecosystems across North America.”

In South Korea Visit, Obama Visits Border and Warns North
PANMUNJOM, South Korea — President Obama warned North Korea on Sunday that its threats and provocations would only deepen its international isolation and jeopardize the resumption of American food aid, and he called on the North to scrap its plans to launch a satellite next month.
Squinting through binoculars from an observation post at the demilitarized zone between North and South Korea, Mr. Obama got a firsthand look at North Korea. The North, with a new leader in place, briefly tantalized the United States weeks ago by raising the possibility of ending the standoff over its nuclear program, only to resume its usual defiance with the recent satellite announcement.